Listen to the strange summer soundtracks

A grasshopper warbler. Picture: STEVE ROUND

A grasshopper warbler. Picture: STEVE ROUND - Credit: Archant

Twice this year I have found myself listening to birds that do not sound at all like birds.

A grasshopper warbler. Picture: STEVE ROUND

A grasshopper warbler. Picture: STEVE ROUND - Credit: Archant

Twice this year I have found myself listening to birds that do not sound at all like birds! The first occasion was whilst camping in Dorset amidst the wild and beautiful heathland bordering the edge of Poole Harbour…

On a still, warm evening in late spring and early summer you are almost guaranteed to hear the strange song of the nightjar issuing out from dusk until dawn on the Dorset heathland. I say ‘almost guaranteed’ because on the very, seemingly perfect, night I chose to lead a small group out into the twilit heathland a deafening silence greeted us! We had to wait a long time but did eventually hear a distant male bird’s song, but not before my birding credentials had almost been teased to tatters. Of course, the very next night, the campsite itself played host to several male nightjars happily calling loudly high above our tents!

The song of the nightjar is best described as a continuous churring sound, rising and falling in pitch. If you hear it you may be forgiven for attributing it to an amphibian or even to a piece of machinery. The nightjar’s song contains 1,900 notes per minute and in the warm, stillness of a summer’s evening, seems to fill the air, mixing with the rising heathland scent of heather and pine. It is a magical experience reminiscent of holiday evenings in the South of France listening to cicadas as the light fades and the day cools off. Perhaps this is what J.A. Baker had in mind as he wrote his beautiful descriptive prose of the nightjar’s song:

“Its song is like the sound of a stream of wine spilling from a height into a deep and booming cask. It is an odorous sound, with a bouquet that rises to the quiet sky. In the glare of day it would seem thinner and drier, but dusk mellows it and gives it vintage. If a song could smell, this song would smell of crushed grapes and almonds and dark wood. The sound spills out and none of it is lost.” (J.A.Baker, The Peregrine, 1967)

The bird itself is no less peculiar than its song with a wide, gaping mouth, reinforcing a sense of the amphibian. Indeed, its closely related family of foreign cousins are called ‘frogmouths’. During the day, it remains perfectly hidden, its brown plumage matching the dry litter of the heathland floor - not revealing itself unless practically stood on.

Like the nighttime jarring of the nightjar another, much smaller bird, has recently been singing its equally un-bird-like notes much nearer to home – at Heartwood Forest on the edge of St Albans. At this time of year, Heartwood is alive with the buzz of insects, cashing in on the abundant supply of nectar from the wildflowers blooming in the warm sun. Calling grasshoppers and crickets herald the start of lazy summer days while boisterous buzzing bees share petal space with the altogether quieter and more delicate butterflies.

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Out walking the dog at Heartwood I paused to take in the scene and listen to the buzz all around me. As I listened I realized that above the stridulations of the grasshoppers a louder, more persistent ‘grasshopper call’ dominated. Almost identical to the song of its insect counterparts this was no insect but a little brown bird aptly named the grasshopper warbler.

Like the nightjar’s song the grasshopper warbler’s reeling notes – likened to the sound of a free-wheeling bicycle or a winding fishing rod spool – rise and fall in pitch and volume as the little bird, its whole body vibrating with the sound, turns its head this way and that. The resulting ‘spray’ of notes has a ventriloquistic quality making it very difficult to locate the bird, often perched just above the long grass on a twig or bush.

Once spotted, the little bird is nothing much to look at with its mottled brown plumage and bright pink legs. Like the nightjar, the grasshopper warbler is perfectly camouflaged and designed to remain hidden and, as a result, both birds are heard far more often that they are seen. This visual secrecy seems to amplify their strange un-bird-like songs and, although unlikely to be heard together, add a layer of mystery to the summer landscape wherever they sing.

The nightjar is sadly now absent as a breeding bird in Hertfordshire but, as I write this, the Heartwood grasshopper warbler is still singing his heart out and proving unusually showy. If you do get a chance to hear him, or indeed a nightjar elsewhere in the country, I’m sure their strange summer soundtracks will captivate you!